The present invention relates to impact power tools and, more particularly, to an improved hand-held pneumatic impact power tool for delicate hand engraving and stone setting in the hand engraving and jewelry fields.
An impact power tool is known from my earlier U.S. Pat. No. 6,095,256, to Lindsay, which may be used for engraving, carving and delicate stone setting operations. A type of device described in my earlier patent is incorporated herein by reference in order to help with the need for further discussion of the types of devices with which the present invention may be employed.
Although the known impact power tool mentioned above provides improved control of delicate hand-working operations not previously available, it would be desirable to provide a impact power tool with additional features to provide greater ease of use. A known embodiment disclosed in my earlier U.S. Pat. No. 6,095,256, to Lindsay, uses a unique feature to adjust the impacting characteristics of the tool. This feature is very beneficial to users, although to modify this impacting adjustment takes valuable time from the jeweler or engraver, as two setscrews need to be loosened before the user can begin to adjust.
Another embodiment disclosed in U.S. Pat. No. 6,095,256, to Lindsay is the a feature that gives more than one placement (chosen by the user) for tubing attachment to the impact power tool. This tubing placement feature uses small plugs to plug holes that are not in use. These small plugs can be easily lost and it takes time to move the tubing attachment to the desired position.
Another feature that needs improvement is how the handles are held on bodies of power tools such as these. The handles must have an airtight seal and yet they must be easily removed for the jeweler and engraver to facilitate cleaning the bore and piston and/or to change to a different weighted piston.
Further, as is addressed in U.S. Pat. No. 5,203,417, to Glaser a power tool that permits users to easily replace the tip of the tool with an alternate tip without having to tighten and loosen a threaded connection or setscrew can speed the work for jewelers or engravers and presents an advantage. The disadvantage of the system disclosed in U.S. Pat. No. 5,203,417, to Glaser is that users are required to fasten all tool tips into a specially designed tool carrier block that is then placed into a mating recess in the power tool. With this system, the user is still required to use a threaded setscrew to fasten the tip into the tool carrier block taking more time than desired.
In accordance with the present invention, a handheld impact power tool that overcomes the problems discussed above and which provides a convenient and unique mechanism for users to adjust length and speed of stroke quickly. The unique mechanism includes an annular band protruding around the outside diameter of the body of the impact power tool that may be turned for adjusting an annular ring in the bore of the impact power tool and thus altering the porting and the impacting characteristics of the impacting piston.
In accordance with the present invention, a handheld impact power tool that provides a feature for attaching air supply tubing to the power tool that may be moved around freely on the outside body of the power tool. The attachment feature includes an annular band around the outside diameter of the body of the power tool that attaches the air supply tubing. This annular band may be rotated and slid along the axis of the body to a position favored by the user.
Further, in accordance with the present invention, a handheld impact power tool that provides a handle that may be manually pushed on and turned to lock. The feature includes more than one pin fixed into the female receptacle handle. These pins are radial aligned and protruding a short distance into the inside diameter of the female receptacle. Included on the outside diameter of the body of the power tool are slots or grooves that permit the pins and handle to slide on and turn and thus tightening against an O-ring between the handle and body, thus sealing and holding the handle onto the body.
Finally, in accordance with the present invention, a handheld impact power tool that provides a simple and convenient construction method that permits quick interchangeability of tool tips. The method includes an o-ring made of a resilient material located inside of the tool holding recess for a friction fit to tool tips. The method also includes a setscrew that is friction fit so as not to vibrate within its mating threads. The screw is perpendicular to the axis of the tool holding hole and is used to index square shank tool tips that are commonly used in the jewelry and engraving fields. The screw is left slightly loosened from the shanks of the tool tips so that tool tips may be removed and replaced quickly. This setscrew may also be used to tighten a round shank tool tip permitting a secure attachment.